Along with the satellites, there are over 380,000 objects in orbit, most of which is space debris (Phys, 2017). Space debris is the term used to denote all artificial satellites and other parts that are now inoperative and unusable, present in Earth’s orbit or re-entering the atmosphere. These objects can start off from the humongous amounts of disintegrations, explosions and in-space collisions of satellites or launch rocket parts that have occurred. As we are about to witness the launch of thousands of satellites in the coming few years, the orbit is not going to heal from space debris anytime soon. Private space giant SpaceX aims to send over 12,000 small-scale internet-beaming objects in the next few years, while the new space player OneWeb also aims to send thousands of satellites into space by 2018, to augment its satellite-based internet services (Scoles, 2017).
It all started in 1957 when after years of hard work, the Soviet Union successfully launched the world’s first artificial satellite, Sputnik 1. Weighing a mere 83.6 kg, the Sputnik 1 was the size of a beach ball, approximately 1.9 feet in diameter. It marked the genesis of the space age and the space race between the United States and the Soviet Union (NASA, 2005). After 60 years of Sputnik 1, there have been about 5250 launches, a number that is skyrocketing because of the entry of many new space players both government and private, including India, which has made a name for itself in a short span of time (Phys, 2017).
Even tiny bits of pieces at high speeds can cause severe damage to satellites, making space junk perilous. There have been instances where space debris has come too close for comfort. Some of them are listed below:
- In 2007, while testing its anti-satellite missile, China decided to destroy one of its deteriorating weather satellites. What followed is the satellite shattering into thousands of pieces, adding to the debris. Although it may not have been a case of space debris collision, it surely resulted in creating more debris. (New York Times, 2007).
- In 2009, ineffective Russian satellite Cosmos 2251 crashed into the Iridium craft (property of Iridium Satellite LLC), disrupting the company’s service. While space debris caused the collision, it created two large clouds filled with space debris, worsening the debris state (Space, 2009).
- In 2007, space shuttle Endeavour suffered a blow from a small piece of space debris which caused a cavity resembling a bullet hole in the space shuttle. Although it did not prove to be lethal, the result could have been different if the size or speed of the junk was even minutely higher (BBC, 2015).
- In 2015, astronauts aboard the International Space Station (ISS) had to take emergency shelter after a piece of junk from an outdated Russian satellite threatened the space station, which is situated roughly 400km above the Earth. Although there was no impact, the satellite passed the space station at a minor distance of 3km. It was only the fourth incident of its kind in the 16-year history of the space station (The Guardian, 2015).
Apart from the dangers space debris poses to the satellites in orbit, re-entering space debris can pose a risk to people on Earth as well. While most of the debris burns up in the atmosphere, there are some components which survive and fall on the surface of the Earth. According to NASA, on an average one tabulated piece of debris has fallen back on Earth every day for the past 50 years. Although there have been incidents, there are no reports of noteworthy damage to people or property. On January 22, 1997, an American woman named Lottie Williams was allegedly the first person to be struck by space junk. The six-inch object that hit her was supposedly from a used Delta II rocket, which crashed into the atmosphere roughly 30 minutes before the accident (Today Science History, 2017). There have been several other instances where small pieces of debris have affected people all around the globe, raising the security risks of a large chunk of debris falling on the ground.
What lies ahead?
Space agencies across the globe are working to tackle the excessive amount of debris orbiting the Earth. The Surrey Space Centre at the University of Surrey is leading the charge with its RemoveDebris mission. The mission is aimed to test novel techniques and perform multiple space debris removal demonstrations (SSTL, 2018). Hempsell Astronautics, a British firm has proposed a system that will collect discarded out-of-date satellites and transport them to a spot termed as ‘graveyard orbit’. This area is situated a few hundred kilometres above the roughly 22,000-mile-high (36,000 km) geostationary ring. On the other hand, researchers from the University of Colorado have proposed the concept of a ‘pulsed electron gun’ to push out-of-date satellites away from the geostationary ring (Pultarova, 2017).
India too is trying to play its part in space debris removal. A team of scientists consisting of members from Indian Space Research Organisation (ISRO) and Physical Research Laboratory (PRL) is assembling a new station atop the Guru Shikhar observatory in Mount Abu, Rajasthan. It will be home to a one-metre wide telescope, equipped with precisely crafted optics and back-end instruments pieced together by ISRO. The new facility will track space debris which includes inactive satellites, wayward electronic parts of space instruments, residue from previous launches and other junk which poses a threat to active satellites.
Space debris brings forth a catastrophic risk, which may need a collaborative effort from all space players, both government and private. As India gears up to fight space debris, it joins other prominent names such as Norway, the United States, Germany and Spain. When the near future holds the launch of thousands of satellites from both multiple agencies, space debris removal programmes can prove to be the boon our orbit direly needs.